It's one big loop, doubled over, then with two limiting knots tied into it to limit extension. So each end is locked to the anchor bolt, then the two pear biners each go around two cords. Kinda hard to read in this picture. But I assure you it's bombproof, I'm the most nervous anchor builder on earth. I think I got it from the John Long book and/or a mountaineer friend who's also an instructor. One or both of those people call it a "quad" I believe.
Not the correct quad set-up. In Climbing Anchors there is a detailed description and close-up photos of how to rig the quad.
This looks like what is known as the equalette, tied on a doubled cordellette.
A handy refernce book is the Climbing Anchors Field Guide, which is a companion book to Climbing Anchors, that is designed to be taken out in the field. On page 80-81 there is a description and photo of the equalette, and on page 87-88 a photo and description of how to rig the quad.
The QUAD rig is when you clip into three of the four strands, leaving one as a back-up, as illustrated in the Climbing Anchors book. The rig pictured here looks like a "doubled equalette" in the way that the carabiners are clipped. Both the QUAD and the doubled equalette are tied the same way to start- just different in the way the carabiners are attached.
I'm not saying it's unsafe, it's just not what we refer to as the QUAD rig.